This device relates to electrical circuits that generate analog output waveforms and more particularly to an operational amplifier ("op-amp") based sine and cosine wave oscillator.
In the field of electronic systems it is often necessary to provide two sine waves in quadrature, or with 90.degree. phase difference between them. This function is always satisfied by oscillators which simultaneously produce sine and cosine waveforms. These outputs are then used as inputs to other types of electronic circuits, such as timing circuits.
In a circuit such as that shown by Berlin, two op-amps are electronically interconnected to function as integrators. (FIG. 6-4, Berlin p. 136). The outputs of op-amps Al and A2, respectively, are sine and cosine waveforms of uniform frequency. The frequency is dependent upon the value of resistance chosen for R and the value of capacitance chosen for C. The greater the product of R.times.C, the lower the frequency output of the device. The value of resistance chosen for R1 is less than that of R so that the circuit begins oscillating immediately upon the application of power.
In a circuit such as that shown by Jung, again two op-amps are electronically interconnected to function as integrators. (FIG. 10-4, Jung p. 365). The integrators are in cascade using positive feedback. R2 is slightly lower in resistance value than the other resistors in the circuit to ensure starting. The outputs of op-amps A1 and A2 deliver sine and cosine waves, respectively, upon the application of power.